Dual ratio drive for rotary shear

ABSTRACT

A dual ratio drive for a rotary sheer comprises a parallel pair of first shafts carrying freely rotatable first gears. A pair of second shafts are rotatable about axes parallel to the axes of the first shafts. Each second shaft carries a shear blade, and a second gear in meshed relationship with one of the first gears. A drive shaft is connectable to one of the second shafts by a first gear set having a high speed ratio, and is connectable to one of the first shafts by a second gear set having a low speed ratio. A clutch alternately engages one or the other of the first and second gear sets to drive the second shafts and their respective shear blades at the different speeds.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to shears employed to subdivide hotrolled steel bar products in rolling mills, and is concerned inparticular with the provision of a dual ratio drive for such shears.

2. Description of the Prior Art

Smaller sized bar products ranging in diameter up to about 16 mm aretypically delivered to dividing shears at speeds ranging as high as 20m/sec, whereas larger bar products having diameters larger than 60 mmtravel at substantially lower speeds, often as low as 1.5 m/sec.Conventionally, the smaller sized bar products are subdivided by highspeed shears, having sufficient kinetic energy to propel the shearblades through successive cutting cycles. However, because of theirlower delivery speeds and larger cross sections, the larger sized barproducts must be directed to shears operating at lower speeds, whereflywheels or the like are needed to develop the energy required toeffect cutting.

The objective of present invention is to provide a dual ratio driveenabling one shear to subdivide both the smaller and larger sized barproducts.

SUMMARY OF THE INVENTION

A dual ratio drive in accordance with the present invention comprises aparallel pair of first shafts carrying freely rotatable first gears. Apair of second shafts are rotatable about axes parallel to the axes ofthe first shafts. Each second shaft carries a shear blade and a secondgear in meshed relationship with one of the first gears. A drive shaftis connectable to one of the second shafts by a first gear set having ahigh speed ratio, and is connectable to one of the first shafts by asecond gear set having a low speed ratio. A clutch alternately engagesone or the other of the first and second gear sets to drive the secondshafts at the different speeds.

These and other features and attendant advantages of the presentinvention will now be described in greater detail with reference to theaccompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a shear incorporating a dual ratio drivein accordance with the present invention;

FIG. 2 is a vertical sectional view taken through the shear of FIG. 1,and showing the dual ratio drive in a high speed mode; and

FIG. 3 is a view similar to FIG. 2 showing the dual ratio drive in a lowspeed mode.

DETAILED DESCRIPTION

With reference initially to FIGS. 1 and 2, a shear incorporating a dualratio drive in accordance with the present invention is generallydepicted at 10. The shear includes a housing structure having front andrear walls 12, 14 and internal partitions 16, 18.

A parallel pair of non-rotatable first shafts 20 a, 20 b is containedwithin the housing. Shaft 20 a extends between the front and rearhousing walls 12, 14, whereas shaft 20 b is shorter and extends betweenthe front wall 12 and the intermediate partition 16. Intermeshed firstgears 22 a, 22 b are rotatably mounted, respectively, on the first andsecond shafts 20 a, 20 b by bearings 21.

A pair of second shafts 24 a, 24 b are mounted by means of bearings 25supported on the front wall 12 and intermediate partition 16 forrotation about axes A₁, A₂ parallel to the axes A₃, A₄ of the firstshafts 20 a, 20 b. Each of the second shafts has fixed thereto arespective shear blade 26 a, 26 b and a second gear 28 a, 28 b. Thesecond gears 28 a, 28 b are in meshed relationship with respective firstgears 22 a, 22 b.

A drive shaft 30 is aligned coaxially with the second shaft 24 b.

A first gear set having a high speed ratio comprises adjacent firstexternally splined ends 32 a, 32 b respectively on second shaft 24 b andthe drive shaft 30.

A second gear set having a low speed ratio comprises a third gear 34surrounding the drive shaft 30 and supported by bearings 35 carried bypartition 18 and a collar 19 in the rear wall 14. Gear 34 is in meshedrelationship with a fourth gear 36 supported by bearings 37 carried bypartition 18 and an end cap 23 in the rear wall 14. Gear 36 is freelyrotatable about the axis A₃ of shaft 20 a, and gear 34 is freelyrotatable about the axis A₂ of drive shaft 30. Gears 22 a and 36 haveadjacent second externally splined ends 38 a, 38 b, and gear 34 has athird externally splined end 39.

A clutch comprises a lever 40 fixed to a cross shaft 42 having anexternal arm 44 (see FIG. 1). Lever 40 carries freely rotatableinternally splined first and second coupling members fifth and sixthgears 46, 48. First coupling member 46 is additionally provided with anouter collar containing a third coupling member ring gear 47. Lever 40is adjustable between a high speed mode as shown in FIG. 2, and a lowspeed mode as shown in FIG. 3.

In the high speed mode, first coupling member 46 is internally meshedwith both of the first externally splined ends 32 a, 32 b to therebymechanically couple drive shaft 30 to the second shaft 24 b, whereassecond coupling member 48 is out of engagement with at least one of thesecond externally splined ends 38 a, 38 b. In the low speed mode, theopposite condition exists, i.e., first coupling member 46 is out ofengagement with externally splined end 32 a, is internally meshed withexternally splined end 32 b, and its coupling member 47 is engaged withthe third externally splined end 39 of gear 34. Second coupling member48 is in meshed relationship with both of the externally splined ends 38a, 38 b to thereby mechanically couple the drive shaft 30 via gears 34and 36 to the first gear 22 a. The lever 40 is alternately adjustablebetween the high and low speed modes by rotating the external arm 44.

A flywheel 50 is supported by bearings 52 on the collar 19 for freerotation about the axis of drive shaft 30. The drive shaft has a secondexternally splined end 54. An axially shiftable clutch collar 56 has afirst internal coupling member 57 in meshed relationship with thesplined drive shaft end 54, and a second internal coupling member 58arranged to coact with an external coupling member 60 on the flywheel toselectively fix the fly wheel 50 to the drive shaft when circumstancesrequire additional momentum, as dictated by product speed and therequired cutting energy.

The above-described alternately adjustable dual ratio drive allows theshear to service a wider range of products, thus resulting in simplermill layouts and important savings in capital costs.

Various changes and modifications can be made to the above-describedembodiment without departing from the scope of the appended claims. Anon-limiting example of one such modification would be the substitutionof a functionally equivalent electrically or hydraulically actuatedclutching arrangement for alternately engaging the dual ratio gear sets.

1. A rotary dividing shear comprising: a pair of shearing blades; a dualratio drive comprising; a parallel pair of first shafts; intermeshedfirst gears respectively rotatably mounted on said first shafts; a pairof second shafts rotatable about axes parallel to the axes of said firstshafts, each of said second shafts having fixed thereto one of said pairof shearing blades, and a second gear in meshed relationship with arespective one of said first gears; a drive shaft arranged coaxiallywith one of said second shafts; intermeshed third and fourth gearsrespectively arranged coaxially with and rotatable relative to saiddrive shaft and one of said first gears; and clutch means operable infirst and second modes to drive said second shafts at respectivedifferent first and second speeds, wherein the first mode causes a firstinternally splined coupling member to shift to a position thatrotationally locks the drive shaft and said one of said second shafts,wherein the second mode causes a second internally splined member toshift to a position that rotationally locks the fourth gear and said oneof said first gears.
 2. The dual ratio drive of claim 1 wherein saidsecond speed is lower than said first speed.
 3. The rotary dividingshear of claim 1 wherein said drive shaft and the said one of saidsecond shafts have adjacent first externally splined ends to mate withsaid first internally splined coupling member.
 4. The rotary dividingshear of claim 1 or 2 wherein said fourth gear and the said one of saidfirst gears have adjacent second externally splined ends, to mate withsaid second internally splined coupling member.
 5. The rotary dividingshear of claim 4 wherein said third gear has a third externally splinedend, and wherein said second mode is achieved in part by mechanicallycoupling the first externally splined end on said drive shaft to saidthird externally splined end.
 6. The rotary dividing shear of claim 5wherein said clutch means comprises a lever carrying said internallysplined first and second coupling members, and means for adjusting saidlever between said first mode in which said first coupling member is inmeshed relationship with both of said first externally splined ends andsaid second coupling member is out of mesh with at least one of saidsecond externally splined ends, and said second mode in which said firstcoupling member is in meshed relationship with the first externallysplined end on said drive shaft and the third externally splined end onsaid third gear, and said second coupling member is in meshedrelationship with both of said second externally splined ends.
 7. Therotary dividing shear of claim 6 wherein the first operational mode ofsaid clutch means results in said second shafts being driven at arotational speed higher than the rotational speed of said second shaftswhen said clutch means is in said second operational mode.
 8. The rotarydividing shear of claim 1 further comprising a fly wheel rotatablymounted on said drive shaft, and second clutch means for selectivelyrotatably fixing said fly wheel to said drive shaft.